ASTM A931-1996(2008) Standard Test Method for Tension Testing of Wire Ropes and Strand.pdf

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1、Designation: A 931 96 (Reapproved 2008)Standard Test Method forTension Testing of Wire Ropes and Strand1This standard is issued under the fixed designation A 931; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last rev

2、ision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the tension testing of wire ropesand strand at room temperature, specifically to determine theminimum

3、 acceptance strength or nominal strength, yieldstrength, elongation, and modulus of elasticity.1.2 The values stated in inch-pound units are to be regardedas the standard. The SI units given in parentheses are forinformation only.1.3 This standard does not purport to address all of thesafety concern

4、s, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific precau-tionary statements are given in 7.3.2, 7.3.4, 7.3.5, and 9.2.2. Refe

5、renced Documents2.1 ASTM Standards:2A 586 Specification for Zinc-Coated Parallel and HelicalSteel Wire Structural StrandA 603 Specification for Zinc-Coated Steel Structural WireRopeB6 Specification for ZincE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of M

6、echanical Test-ingE8 Test Methods for Tension Testing of Metallic Materials3. Terminology3.1 The terminology relating to tensile testing in Terminol-ogy E6applies to this test method. In addition, the followingdefinitions for wire rope will apply:3.2 Definitions:3.2.1 abrasionfrictional surface wear

7、 on the wires of awire rope.3.2.2 aggregate areasee area, metallic.3.2.3 aggregate strengththe strength derived by totallingthe individual breaking strengths of the elements of the strandor rope. This strength does not give recognition to thereduction in strength resulting from the angularity of the

8、elements in the rope, or other factors that may affect efficiency.3.2.4 area, metallicsum of the cross-sectional areas of allwires either in a wire rope or in a strand.3.2.5 breaking strengththe ultimate load at which a tensilefailure occurs in the sample of wire rope being tested.3.2.5.1 Discussion

9、The term breaking strength is synony-mous with actual strength.3.2.6 cablea term loosely applied to wire rope, wirestrand, and electrical conductors.3.2.7 centerthe axial member of a strand about which thewires are laid.3.2.8 classificationgroup or family designation based onwire rope constructions

10、with common strengths and weightslisted under the broad designation.3.2.9 constructiongeometric design description of thewire ropes cross section. This includes the number of strands,the number of wires per strand, and the pattern of wirearrangement in each strand.3.2.10 corethe axial member of a wi

11、re rope about whichthe strands are laid.3.2.11 fiber corecord or rope of vegetable or syntheticfiber used as the core of a rope.3.2.12 galvanized ropewire rope made up of galvanizedwire.3.2.13 galvanized strandstrand made up of galvanizedwire.3.2.14 gradewire rope or strand classification by strengt

12、hor type of material, that is, Class 3, Type 302 stainless,phosphor bronze, etc. It does not apply to strength of theindividual wires used to manufacture the rope or strand.3.2.15 independent wire rope core (IWRC)a wire ropeused as the core of a larger wire rope.3.2.16 inner wiresall wires of a stra

13、nd except the outer orcover wires.1This test method is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.03 on Steel Rod and Wire.Current edition approved March 1, 2008. Published March 2008. Originallyapprove

14、d in 1994. Last previous edition approved in 2002 as A 931 96 (2002).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM

15、website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.17 lay(a) the manner in which the wires in a strand orthe strands in a rope are helically laid, or (b) the distancemeasured parallel to the axis of the rope (or strand) in w

16、hich astrand (or wire) makes one complete helical convolution aboutthe core (or center). In this connection, lay is also referred to aslay length or pitch.3.2.18 minimum acceptance strengththat strength that is2 % lower than the catalog or nominal strength. This toler-ance is used to offset variable

17、s that occur during samplepreparation and actual physical test of a wire rope.3.2.19 modulus of elasticitythe slope of the elastic portionof the stress-strain curve. The ratio of stress to correspondingstrain below the proportional limit. This value is generallytaken between 20 and 50 % of the nomin

18、al strength.3.2.20 nominal strengththe published (catalog) strengthcalculated by a standard procedure that is accepted by the wirerope industry. The wire rope manufacturer designs wire rope tothis strength, and the user should consider this strength whenmaking design calculations.3.2.21 socketgeneri

19、c name for a type of wire rope fitting.3.2.22 stranda plurality of round or shaped wires heli-cally laid about a center.3.2.23 wire ropestrands helically laid around a core.3.2.24 wire strand core (WSC)a wire strand used as thecore of a wire rope.4. Significance and Use4.1 Wire rope tests are genera

20、lly to be performed on newrope. The use of wire rope in any application can reduceindividual wire strengths due to abrasion and nicking that willresult in the wire rope strength being reduced. Damage to theouter wires will also lower the maximum strength achievedduring tension testing.4.2 The modulu

21、s of elasticity of wire rope is not consideredto be a standard requirement at this time. The determination ofthis material property requires specialized equipment andtechniques.4.3 Rope to be tested should be thoroughly examined toverify that no external wire damage is present. If present, itshould

22、be noted. When possible, a new undamaged sampleshould be obtained for testing.4.4 End attachments and their installation can directly affectbreaking strength achieved during testing.Any attachment thatcan be used to directly achieve the required rope breakingstrength can be used. Standard testing wi

23、th a poured socket,using zinc, white metal or thermoset resin, has been consideredthe most efficient. Proficiency in attachment of any fitting canhave a direct effect on the final test results.5. Interferences5.1 Visual examination of the sample for any damage toouter wires should be done. If any da

24、mage is evident, thesample should not be used. The purpose of this test method isto verify the nominal or maximum strength the wire rope orstrand can achieve.5.2 Measurement of the rope or strand sample is necessaryto document the size, length between end attachments, andlength of lay of the rope if

25、 necessary. Further details regardingthis will be discussed in test results.5.3 The length of test specimen shall not be less than 3 ft,(0.91 m) between sockets for wire ropes up to 1 in. (25.4 mm)diameter, inclusive, and not less than 5 ft (1.52 m) betweensockets for wire ropes 118 in. (28.6 mm) to

26、 3 in. (77 mm)diameter. On wire ropes larger than 3 in. (77 mm), the clearlength of the test specimen shall be at least 20 times the ropediameter.6. Apparatus6.1 Testing MachinesMachines used for tension testingshall conform to the requirements of Practices E4. The loadsused in determining tensile s

27、trength and yield strength shall bewithin loading range of the tensile machine as defined inPractices E4.6.2 Gripping Devices:6.2.1 GeneralVarious types of gripping devices may beused to transmit the measured load applied by the testingmachine to test specimens. To ensure axial tensile stress within

28、the gauge length, the axis of the test specimen should coincidewith the center line of the heads of the machine.Any departurefrom this requirement may introduce bending stresses that arenot included in the usual stress computation.6.2.2 Wedge GripsTesting machines usually are equippedwith wedge grip

29、s. These wedge grips generally furnish asatisfactory means of gripping long specimens of ductile metal.If, however, for any reason, one grip of a pair advances fartherthan the other as the grips tighten, an undesirable bendingstress may be introduced. When liners are used behind thewedges, they must

30、 be of the same thickness and their facesmust be flat and parallel. For best results, the wedges should besupported over their entire lengths by the heads of the testingmachine. This requires that liners of several thicknesses beavailable to cover the range of specimen thickness. For propergripping,

31、 it is desirable that the entire length of the serratedface of each wedge be in contact with the specimen. Specially-designed round-shaped grips may have to be used for testingrope or strand. It is essential that all wires in the rope or strandare uniformly gripped when the load is applied.6.2.3 Con

32、ical GripsConical grips are constructed so thatwhen they are fitted together, a conical-shaped cavity existswhich will hold a cone socket wire rope or strand andattachment (fitting).7. Sample Preparation and Preparation of EndAttachments7.1 Poured sockets are considered to be the most efficientand s

33、hould be used due to their ability to distribute the loadevenly in the wire rope when installed properly. Procedures forthe proper installation of poured end attachments can be foundin socketing procedures.7.2 Other end attachments such as grips may be usedprovided the required loading is achieved.7

34、.3 Sample Preparation Procedures:7.3.1 SocketingZinc-Poured Socketing:7.3.1.1 Measuring the Rope Ends to be SocketedThe ropeend should be of sufficient length so that the ends of the unlaidwires (from the strands) will be at the top of the socket basket(see Fig. 1(a).A 931 96 (2008)2FIG. 1 Wire Rope

35、 for SocketingA 931 96 (2008)37.3.1.2 Apply Serving at Base of SocketApply a tight wireserving band at the point where the socket base will be for alength of two rope diameters (see Fig. 1(b) and 1(c).7.3.1.3 Broom Out Strand WiresUnlay and straighten theindividual rope strands and spread them evenl

36、y so that theyform an included angle of approximately 60. Unlay the wiresof each individual strand for the full length of the rope end,being careful not to disturb or change the lay of the wires andstrands under the serving band. Unlay the wires of an indepen-dent wire rope core in the same manner.

37、A fiber core should becut out and removed as close to the serving band as possible(see Fig. 1(c).7.3.2 Clean the Broomed-Out EndsA suggested cleaningsolvent for this step is SC-5 methyl chloroform. It is alsoknown under the names chlorothane VG and 1-1-1 trichlore-thane. Warning: Breathing the vapor

38、 of this solvent is harm-ful; it should only be used in a well-ventilated area. Be sure tofollow the solvent manufacturers instructions, and carefullyobserve all instructions printed on the label. Some non-chlorinated solvents are adequate and are preferable if avail-able.7.3.2.1 Swish the broomed-o

39、ut rope end in the solvent, thenbrush vigorously to remove all grease and dirt, making certainthat the wires are clean to the very bottom close to the servingband (see Fig. 1(d). Additionally, a solution of muriatic acidmay also be used. If, however, acid is used, the broomed-outends should be rinse

40、d in a solution of bicarbonate of soda so asto neutralize any acid that may remain on the rope. Care shouldbe exercised to prevent acid from entering the core; this isparticularly important if the rope has a fiber core. Where it isfeasible, the best and preferred cleaning method for rope endsprior t

41、o socketing is ultrasonic cleaning. After this cleaningstep, place the broomed-out end upright in a vise allowing it toremain until all solvent has evaporated and the wires are dry.7.3.2.2 Solvent should never be permitted to remain on therope or on the serving band since it will run down the wiresw

42、hen the rope is removed from the vise.7.3.3 Dip the Broomed-Out Rope Ends in FluxPrepare ahot solution of zinc-ammonium chloride flux comparable toZaclon K. Use a concentration of 1 lb. (453.6 g) of zinc-ammonium chloride to 1 gal (3.774 L) of water, maintain thisat a temperature of 180F (82C) to 20

43、0F (93C). Swish thebroomed-out end in the flux solution, then place the rope endupright in the vise until such time as the wires have driedthoroughly (see Fig. 1(e).7.3.4 Close Rope Ends and Place SocketUse clean wire tocompress the broomed-out rope end into a tight bundle that willpermit the socket

44、 to be slipped on easily over the wires (seeFig. 1(f). Before placing the socket on the rope, make certainthat the socket itself is clean and heated to 200F (93C) to400F (204C). This heating is necessary in order to dispel anyresidual moisture, and to prevent the zinc from coolingprematurely. Warnin

45、g: Never heat a socket after it is placed onthe rope. To do so may cause heat damage to the rope.7.3.4.1 After the socket is on the rope end, the wires shouldbe distributed evenly in the socket basket so that zinc cansurround each wire. Use extreme care in aligning the socketwith the ropes centerlin

46、e, and in making certain that there is aminimum vertical length of rope, extending from the socket,that is equal to that specified in 6.3.7.3.4.2 Seal the socket base with fire clay or putty, but makecertain that this material does not penetrate into the socketbase. Should this occur, it would preve

47、nt the zinc frompenetrating the full length of the socket basket, therebycreating a void that would collect moisture after the socket isplaced in service.7.3.5 Pour the ZincThe zinc used should meet Specifica-tion B6Grade (1) High Grade. Pour the zinc at a temperatureof 950 to 970F (510 to 521C) (se

48、e Fig. 1(h); makeallowances for cooling if the zinc pot is more than 25 ft. fromthe socket. Warning: Do not heat zinc above 1200F (649C)or its bonding properties will be lost, and heat damage willoccur to the rope. The zinc temperature may be measured witha portable pyrometer or a Tempilstik. Remove

49、 all dross beforepouring. Pour the zinc in one continuous stream until it reachesthe basket top and all wire ends are covered; there should be no“capping” of the socket.7.3.6 Remove ServingRemove the serving band from thesocket base; check to make certain that the zinc has penetratedto the socket base (see Fig. 1(i).7.3.7 Lubricate the RopeApply wire rope lubricant to therope at the socket base and on any rope section where theoriginal lubricant may have been removed.8. Thermo-Set Socketing8.1 Before proceeding with a